Electric cooking appliance



Feb. 15, 1944. l. JEPsoN r2,342,077

ELECTRIC COOKING APPLIANCE Filed Dec.' 9, 1940 '2 sheets-sheet 1 Feb.15, 1944. l. JEPSON 4ELECTRIC COOKING APPLIANGE 2 Sheets-Sheet 2 FiledDec. 9, 1940 ing waiiles but adapted various safety standards. Whenbaker with the bottom cover removed;

' .and the heating element therein;

f vention.

Patented Feb. 15, 1944 2,342,077 ELECTRIC COOKING APPLIANCE Ivar Jepson,Chicago, lll

Flexible Shaft Com ration of Illinois l assignor to Chicago Chicago,IIL, a corpo- Applcation December 9, 1940, Serial No. 369,182 8 Claims.ICI. 21S-19) 'I'he invention relates to improvements in electric cookingappliances such as those referred to as wallie irons or bakers commonlyused for bakfor other cooking purposes.

One of the objects of this invention is to provide a generally improvedelectric cooking appliance adapted for cooking functions such as areperformed with a grid or grill, and it has more particular reference towallie baking appliances of the type having a thermostatic switch forconl trolling the cooking period. To this end the in.

vention aims to provide certain novel features of constructioneconomical to manufacture, dependable in operation', and easy toservice. These construction features will be described more particularlyhereinafter.

Another object of the invention is to provide a thermostatic control forregulating the temperature of the grid plates of the baker, which is soshielded and arranged that it is directly responsive to the temperatureof the grid plates and substantially insensitive to the direct radiationfrom the heating element and from convection currents.

Still another object of the invention is to provide a simplified' meansfor mounting the elements of the thermostat', including the lead membersand the manual control means, to a portion of one of the grid plates.

In devices having an electric heating element, such as an electric wamebaker, the cord supplying the current must be maintained below apredetermined temperature in order to comply with a conventionalcord-support cap or terminal box is used in abutment with the case ofthe baker baker embodying the invention;

Fig. 2 is a fragmentary bottom view of the Fig. 3 is a'top'elevation ofthe reilector plate 3nd Fig. 4 is Referring to thedrawings, 5 is a lowercase of substantially square shape having inwardly where the cord 1enters the baker, it hasbeen found that the cord a diagramof thecircuitinfthein- .it will become rolled flange portions B andl at itsupper and lower edge, respectively. A lower grid 8 having i quadrantscontaining like grid designs is mounted on the case 5 across the topthereof in a spaced .hold it rmly within the said case 5. A top grid I Iis supported on a one-piece upper case I2 having a crown-shaped toppanel I3 and depending side walls I4. The grid II is secured firmly tothe front portion of the top case by a pair of screws I5 which enterthrough the case I2 into corresponding bosses I6 integral with the gridIl. At the rear of the grid I I, Gullmite screws I1 are entered into twopairs of bosses I8 which are integral with the grid II, the screws I'Ialso serving to fasten a pair of upper hinge members I9 (only one shown)to the rear side wall I4 of the case I2. The hinge members I3 haveintegral, outwardly splayed portions on each side thereof which abut thecase I2, the screws. II being inserted therethrough.

In the embodiment here shown for purpose of illustration, theinner-portion of'the upper grid is identical with that of the lower gridand is disposed immediately above it when the upper case I 2 is loweredinto the baking position on the lower case 5. In this position aperipheral ilange 2| of the upper grid rests upon a shoulder portion 22of the grid to maintain a spacing 23 between the upward and downwardprojections of the respective lower and upper grids. A lip 24 integralwith the lower grid extends upwardly from the periphery thereof to asubstantial depth, preferably approximating the depth of the upper grid,as shown. This acts as a batter-retaining wall to restrain the batterfrom overiiowng onto the outer surface of the case 5. Batter locatedbetween the grids will expand as it becomes heated through-the grids,and as a consequence will tend to force itself out from betweenK theshoulder 22 and the peripheral 'flange 2l.. However, such escapingbatter will taining trough 25 provided by the lip 24 where hardened bythe heat to prevent further upward movement of overowing batter and todefine a definite pattern at the marginal edge of the waiiie. Even-if anexcessive amount of batter is introduced between the grids its overflowwill be restricted in the same manner, that is, by a seal of hardenedbatter being formedpf-l a confined and denite shape about the innersidibf the 11p 24. The grid structure here disclosed is the subjectmatter of an application for patent merely rise in the upright'reorWilliam F. Bisley, Serial No. 491,431, filed dune .'19, 1943; and itshould be understood that in the the plates 2t. These lugs are insertedthrough e holes in the case 5 and upset against a backing plate on theinner side thereof. In the closed position, relative upward and downwardmovement of the top case i2 with respect to the lowercase 5 is permittedby slots 2 in the plates 2t in which the pins 28 ride upwardly anddownwardly. This movement allows the top grid to move upwardly inresponse to the expansion of the baking wae to enlarge the space 22. theweight of this top case assembly providing the desired pressure on thewaiie during the baking period.

A reector plate 29 having curved, upwardly extending side walls ispositioned in aparallel spaced relation beneath the bottom grid, beingsecured by stud bolts 3i which enter into depending bosses 32 integralwith said grid. A bottom plate 35 encloses the bottom of the cases,being attached thereto by screws 3d which enter into the lower ends ofstuds 3i. Four feet 35 of a hardened rubber composition are secured byrivets 316 at the four corners of the bottom plate 33 to support thewame'baker in a raised relation from the surface of a table to preventburning or scorching of the table surface.

As is illustrated in Fig. 3, a heating element consisting of a coiledwire is mounted on insulator buttons 3i spaced about the reflectorplated. Each insulator button 3l has a center .slot 38 adapted toreceive 'a supporting pin struck up from the plate 29 and integraltherewith. The head @d of each pin is twisted at a right angle to theslot @t to secure the button in position on the reflector plate. Theheating element for the plate 29 is composed of two identical sectionsdi and d2 which are connected in series, as illustrated in Fig. 4.Terminals d3 and dd of a conventionahdesign are `mounted on atriangular-shaped mica insulator d5, an additional mica insulator dabeing mounted on the opposite side of the plate 29. The heating. elementseotions terminate at the posts tl and 381. Electrical connectionbetween the two sections of this element consists of a lamp shuntresistance da Y and a iamp circuit consisting of bus bars 5i and 52 andasignal lamp bulb 53. Both of these connections are located on the underside of the plate 2t, as shown by Fig. 2. `The threaded base 5d of thelamp bulb is screwed into a socket member 55 integral with thebus bar 5land at right angles thereto. In this position the rear end of the bulbmakes contact with-a spring contact 55 integral with the bus bar 52. Theforward ends of the bus bars 5i and 52 are secured to the plate 29 by acommon rivet 51, being insulated from one another by a mica piece 59.

A reflector plate 59 similar in construction to the plate 29 is mountedin a parallel spaced relation above the top grid il and is supported.

shielded in a coiled spring it that assumes a semi-circular shape whenthe top case i2 of the baker is in a lowered position. Thus, the springl@ does not interfere with the lowering and raising of the top caseportion of the baker and yet affords protection` for the leads therein.The ends of the spring lli are secured to the respective case 5 and topcase l2 by a threaded guide l5 that fastens in a nut ld, while the otherend of the spring i3 is held within a crimped annulus l?.

. The thermostatic switch 5t controls theseries circuit that energizesboth heating elementA sections di and d2.. Power from the lead ti isconducted through a bus bar 1,8 that acts as a conductor between aterminal l@ and a switch con= tact blade 8|. The thermostat circuit isclosed by contacts t2 and 83 carried by switch blades di and 8d,respectively. The switch blade ed is connected with a bus bar 35 thatacts as a conductor to the terminal d3 to which one end of the gridelement section li is connected. A bimetallicblade 26 having a porcelainbuttonv till on its free end brakes contact between the con tact points82 and 33 when the heat of the grid t reaches a predeterminedtemperature. The bus `bars it and 85, together with the switch blades 8iand 8d, are supported as a unit of assembly on a bracket @t which isdetachably mounted on a lug t9. Mica insulators 9i are positioned oneach side of the right angle end portions of the bus bars i8 and 85 toinsulate them from the bracket t3. Rivets 52 and washers 93 securelyfasten the assembly, consisting of the mica insulators ai, the endportions of the bus bars it and 85, and the contact leaves ti and 3d tothe bracket 88. The bimetallic blade 86 is partially enclosed by a wallstructure extendingV downwardly from the lower grid t, being integraltherewith. One section of this wall has an angular shaped portion 9d,'while the other has a portion Q5 to one .end portion 96 of which thebil metallic blade 8a is riveted. The wall sections. td and 95v providea means for shielding the' tact between contact points 82 and 83 whenthe lower grid reaches a predetermined temperature on bosses 6l that areintegral with the top grid y il. Screws 62 rigidly secure the plate 59to the bosses GI. A heating element 63 is mounted on buttons 64 in thesame manner as the heating element sections 4l and 42. The pattern ofthis element with respect to the buttons te and the plate 59 issubstantially the same as that shown Fig. 3. The element 63 has itstermini in a to control the cooking periodand the degree to which thewailie is to be baked. By reason of this shielding wall structure thebimetallio blade 8S will be less disposed to respond to convectioncurrents set up beneath the lower grid, in particular during thepreheating stages when the case. 5, bottom cover 33, and other'parts ofthe baker are changing temperature at a greater rate than the grid. Whenbatter is poured into the preheated grids, the lower grid willbe'immediately'cooled to a temperature below the baking range. It isnecessary then that 'the bimetalliov blade 86 doesvnot break thecontacts 82 and 83 radiating from, the element sections 4| and 42 andthe reflector plate 29, which would vundergo only a slight temperaturechange in comparison I to the lower gri'd upon the introduction of thevided with slots batter. Consequently, by this means the sensi- I tivityof the bimetallic blade 86 to the temperature of the lower gridisinc'reased in the invention during the operating stages of the baker,whereby the constancy of the grid temperature is better maintained.

An adjustment for the thermostat assembly is provided by a means foradjusting the distance between the contact blade 64 and the bimetallicblade 86. To this end, an adjustment rod 91 is rotatably mounted in atransverse relation to the contact blades 8| and 94 in the case 5. Theinner end of the rod 91 is threaded for a mounting in a nut 98 thatispressed `within a boss 99 integral with the wall member 95. Thisthreaded end of the rod 91 projects beyond the boss 99 and contains aporcelain insulator which engages the contact blade 6|. The opposite endof the rod 9,1 has an adjustment knob |02 se cured to an end portionthat extends outside the case 5. As the knob |02 is turned through anarc of approximately 180, the rod 91 will be screwed inwardly to movecontact blade 84 a greater distance from the porcelain button 61 .insuch a manner that the bimetallic blade 86 will have to move a greaterdistance in response to the grid heat to break the circuit betweencontacts 82 and 83. A bearing |03 is provided at the outer end of therod 91 and is secured to the case by aclip |04. 'Ihe bearing |03 alsosecures a semi-circular calibrated dial |05 containing an opening for anindicator window |06 that is in registration with the bulb 53. It isclear that when the baker is turned on by plugging the leads 66 and 61into an electrical circuit, the heatingl elements will. be energized andthat the signal lamp 53 will be lighted. When the temperature of thegrids has reached a predetermined degree, the blade 86 will break thecircuit to the heating elements, thereby turning off the signal lamp. Byobserving the signal lamp turning off through thefindicator Window |06,the operator can determine when the grids have reached the predeterminedbaking temperature required for the introduction of the batter. Aftersupplying the batter, the element circuits are again energizedautomatically by the thermostat 68. The operator then leaves the batterto bake without attention until the signal lamp again turns oi,indicating the restoration of the grid heat tothe predeterminedtemperature, at vwhich time the waflle will be done and ready forserving.' During this baking period the thermostat assembly willmaintain the grids at a constant temperature to avoid burning and insurethe proper temper'ature for the baking of the waille. The rel` ativedarkness or lightness of the wallie is controlled by the movement of theknob |02 between its extreme positions, in one of which the grid will bemaintained at a temperature sultable for light wailles, while in theother for dark` waffles, the in-between ranges being for medium baking.The power leads 66 and 61 enter the baker through a box |01 that abutsthe case 5, being secured thereto by screws |08 that enter the box|01.through a re-enforcing bracket |09 to prevent undue heatingV of thecord containingleads 66 and 61 at the point yat which it enters thebaker case 5. The box |01 is proin registration on the upper and lowersides thereof. This permits circula.- tion of air through the box andaround the cord, whereby the cord is maintained at a temperature thatsatises the requirements of thel lire underwriters. In order to preventstrains on -the terminals at the baker end of the cord, a

clamping means is provided by the clamp members ||2 which are struckfrom the bracket |09. These members H2 clamp the cord at a point havingheat resisting insulation I3 so as to relieve the leads from pullingstrains.

A pair of oppositely disposed handles are provided on the case 5 on eachside of the baker for lifting the complete unit'. A third handle ||4 ofa like low heat conducting composition is secured to the front end ofthe top case |2, providing a convenient means for raising and loweringthe top case assembly during the operating periods. e

Among the construction features of the invention will be noted thesimple and practical method of mounting the heating elements on thereflectorplates; the mounting of the thermostat blade on a lug. cast onthe under side of the lower grid and the mounting of the contact bladeson vanother lug cast on the under side of the lower grid, the contactblades being preferably a part of an assembly unit which includesterminal bus bars; the rod adjustment of the contact blades; themounting and arrangement of the signal lamp; and the assembly wherebyall of the operating parts associated with the f lower grid are mountedand connected from the not wish to be limited thereto bottom of thegrid. It will be observed that this construction requires but a minimumamount of machine work on the lower grid and that the thermostat partsand switch mechanism, together with the complete connections, areeffected in such simple manner as to avoid the necessityl ofindividually mounting or connecting a large number of parts on the lowergrid.

While I have shown a particular embodiment of my invention, it will .beunderstood that I do l since many modiilcations may be made, and Itherefore contemplate by the appended claims to cover any suchmodications as fall within the true spirit and scope of my inventionJ l.In an electric cooking appliance, in combination, a grid, a heatingelement for said grid, a circuit for said heating element, athermostatic switch in said circuit including a thermostat blade andcontact blades biased to circuit closing contact, the grid having lugson. the -back thereof, said .thermostat blade being iixedly mounted onone of said lugs, an adjusting rod threaded in one of said lugs andcoacting with said blades to vadjust their relation to the thermostatblade and f stantlally enclose the thermostat blade arranged to increaseits sensitivityto grid temperature and to substantially shield the bladefrom the heating element, the thermostat blade` being xed' at one end tosaid wall means in good heat conduction therewith in a plane normal tothe rearg facer of the grid, a circuit for the heating element includinga pair of contact blades normal to the rear face of the grid and biasedfor closing the circuit, one of said contact blades arranged in coactingrelation with the thermostat blade so as to be operated thereby to openthe circuit in response to a predetermined grid temperature, and anadjustment rod threaded through the wall means and arranged to directlycoact at its iriner end with a switch blade and manually rotatableat itsouter end to move the contacting switch blades to a greater or lesserdistance relation with respect to the4 operating end of the thermostatblade whereby the blade contacts will be actuated in response to thegrid heat to break the circuit between the blade contactsat higher orlower temperatures according'to the setting of said rod.

3. An electric cooking appliance as set forth in claim 2, in which thecontact blades are part of a unit of assembly including a bracketdetachably mounted on the grid and including bus bars having electricalconnection with thecontact blades, the bus bars and blades beinginsulated from said bracket, the thermostat blade and the adjusting rodeach having an insulation contact member in coaction with the -contactblades, and said unit of assembly being removable from the gridindependently of the thermostat blade and the adjusting rod.

4. In an electric cooking appliance, in combination, a grid, a reectorplate mounted at the back of and spaced from the grid, a heating elementbetween the grid and the plate, a thermostat blade, wall meansprojecting outwardly from the, back of the grid to substantially enclosethe thermostat blade arranged to increase its sensitivity to gridtemperature and to substantially shield the blade from direct radiationfrom the heating element, the thermostat blade being flxed 'at one endto said wall means in good heat conduction therewith in a plane normalto the rear face of the grid, a circuit for the heating elementincluding a pair of contact blades located between said wall ymeansnormal to the rear face of the grid and biased for closing the circuit,one of said contact blades extending beyond the other and arranged incoacting relation with the thermostat blade so as to be ,operated4thereby to open the circuit in response to a predetermined gridtemperature, and an adjustment `4 rod threaded through the wall meansand arranged to directly coact at its inner end with the adjacent switchblade and manually rotatablel at'its outer end to move the contactingswitch blades to a greater or lesser distance relation with respect tothe operating end of the thermostat blade whereby the blade contactswill be actuated in response to the grid heat to break the circuitaaaacrr in claim 4, in which the contact blades are part of a unit ofassembly including a bracket detach- `ably mounted on the grid andincluding bus bars having electrical connection with the contact blades,the .bus bars and blades being insulated from said bracket, and terminalposts for the heating element extending throughand mounted on thereflector plate, said bus bars extending through the reflector plate andconnected to said terminal posts at the outer side of said plate.

6. In an electric cooking appliance, in combination, a'g'rid, areflector plate mounted at the back of and spaced from the grid, 'aheating ele ment between the grid an'd the plate, and a cir4 cuit fortheheating` element including terminal posts extending through the plateinsulated therefrom and connected at-the inner end to the heatingelement, a bus bar for each terminal post located at the outer side ofthe reilector plate and Aconnected at one end to its respective terminalpost, one bus bar havingan outwardly turned portion vshaped to provide alamp socket and the other bus bar having an outwardly turned portion inalignment with said socket to provide a lamp contact, a lamp bulblthreaded into saidv bus bar socket and making contact with said bus barcontact, anda thermostat switch in the circuit including a thermostatmember responsive to temperature of the grid to open the circuit atapredetermined temperature.

7 electric appliance as set forth in claim 6, including a lamp shuntresistance between .said terminal posts.

8. In an electric cooking appliance, in combination, a grid, a heatingelement for heating the grid, a thermostat blade, a side wall structureintegral with and projecting outwardly from the back of the gridarranged to provide an enclosure for the thermostat blade to increaseits sensitivity to grid temperature and to substantially shield theblade from the heating element, the thermostat blade being iixed at oneend to said side wall structure in good heat conduction therewith in aplane normal to the rear face of the grid, a cricuit for the heatingelement including switch contact blades 'normal to the rear face of thegrid arranged in coacting relation with the thermostat blade so as to beoperated thereby to cause opening and closing 'of the circuit in.response to changes in grid temperature, andan adjustment rod threadedthrough said side wall structure and arranged to directly coact at itsinner end -with one ofv said switch blades and manually rotatable at itsouter end to move one-of said switch blades to a greater or lesserdistance relation with respect to the operating end of the thermostatblade whereby said switch blades .will be actuated in 'response to thegrid heatl to control said heating circuit at .higher or'lowertemperatures according to the

